Disposable diapers typically have a substantially rectangular absorbent pad and side portions that are folded toward each other, that is, toward the longitudinal centerline of the diaper and against the pad. However, the fold portions are usually positioned such that the opposing edges of the fold portions do not reach each other, but are spaced apart. Where the fold portions include pad material, a space between the folded edges having a thickness approximately equal to the thickness of the pad material in the fold portions is formed between the fold portions. In those types of diapers in which the pad is shaped or contoured to form a narrower portion to allow space for the wearer's legs, the volume of the void space between the opposite edges of the fold portions increases substantially. In addition to the longitudinal side portions being folded toward each other and against the central portion of the diaper, for purposes of packaging, the front and rear sections of the diaper are folded into engagement with each other along a transverse line dividing the diaper into front and rear sections. The void spaces between the longitudinal fold portions in the front section and in the rear section of the diaper are thus combined to form a single larger void space in the fully folded diaper which, to the extent that it is retained after the diaper is placed in a package, is wasted space. To the extent that the folded diaper is compressed to eliminate the void space, the diaper is distorted to decrease absorbent capacity, to detract from the appearance of the diaper and create packaging problems when using automatic high-speed packaging equipment. A related folding problem involves the folding of the side portions, including the absorbent material they contain, consistently along a longitudinal fold line, to provide a uniform width diaper when fully folded. Similar to folding of the front and rear sections of the diaper together, uniform folding of the diaper side portions enhances the appearance of the diaper and minimizes packaging problems.
Another problem which is common to disposable diapers is the need for increased fluid absorbent capacity. One of the areas of the diaper at which it is particularly important to have a large amount of absorbent capacity is in the front portion of the diaper because this is the area normally directly wetted by infants and because of the tendency of urine to flow to this area of the diaper when the baby is crawling or sleeping. There have been a wide variety of suggested solutions for increasing the absorbent capacity of the diaper in general and increasing the absorbent capacity of the diaper in the frontal region in particular. Typical of these is the arrangement illustrated in U.S. Pat. No. 3,926,189 to Taylor. This patent discloses a main pad having an auxiliary portion extending from the main pad at approximately the transverse centerline of the diaper. The auxiliary pad portion may be folded forward to the front area of the diaper when the baby is in a sleeping position or the diaper is to be worn by a boy baby to thereby gain the increased front absorbent capacity.
It is a principal object of this invention to locate or distribute absorbent pad material that is auxiliary to the main absorbent pad of a disposable diaper at positions which assist in folding the diaper to a uniform size and shape and utilize void spaces for absorbent material to increase the absorbent capacity of the diaper or maintain the absorbent capacity of the diaper while providing a thinner less bulky overall diaper.